/Engine/Plugins/Runtime/nDisplay/Source/DisplayClusterOperator/Public/IDisplayClusterOperator.h
Gets a list of all nDisplay root actor instances that are on the currently loaded level
void GetRootActorLevelInstances ( [TArray](API\Runtime\Core\Containers\TArray)< [ADisplayClusterRootActor](API\Plugins\DisplayCluster\ADisplayClusterRootActor) * > & OutRootActorInstances )